Peroxy compounds



United States Patent 36,055 63 US. Cl. 260-610 8 Claims Int. Cl. C07c 73/00, 73/08 ABSTRACT OF THE DISCLOSURE Organic peroxidic compounds can be stabilized by forming a composition which comprises at least one organic peroxide together with a stabilizing quantity of dipicolinic acid. The stabilization is particularly effective with hydroperoxides and ketone peroxides.

This invention relates to the stabilisation of certain organic peroxidic compounds, more especially organic hydroperoxides and ketone peroxides.

It is often desired to store such compounds in sealed containers for extended periods. Thus decomposition, with consequent evolution of gas, must be kept strictly in check to avoid risk to bursting the containers. It is an object of the invention to increase the stability of an organic hydroperoxide or ketone peroxide to render it more suitable for such storage.

It is known that inorganic peroxidic compounds such as hydrogen peroxide can be stabilised by a variety of stabilising agents. Some of these stabilisers have also been found effective with solutions of various peroxy acids. It has, however, been found that it is not possible automatically to employ for stabilising an organic hydroperoxide or ketone peroxide a stabiliser which is known to be suitable with hydrogen peroxide and/or a peroxy acid. Some were found ineffective while others decreased rather than increased the stability. Thus there arose the somewhat unexpected problem of finding a suitable compound which would enable the object of providing an organic hydroperoxide or ketone peroxide of increased stability to be realised.

According to the present invention there is provided a composition comprising at least one organic peroxide selected from hydroperoxides and ketone peroxides, and a stabilising quantity of dipicolinic acid.

Examples of peroxides whose stability is increased when they are made into a composition in accordance with the invention, are normally liquid ketone peroxides such as methyl'ethyl ketone peroxide or methyl iso-butyl ketone peroxide, organic hydroperoxides which are normally liquids e.g. t-butyl hydroperoxide or cumene hydroperoxide and pastes or solutions madefrom normally solid organic ketone peroxides, e.g. cyclohexanone (and/or methyl cyclohexanone) peroxide with a suitable inert diluent.

Normally up to 500 ppm. of dipicolinic acid, based on the weight of the peroxide content of a composition in accordance with the invention, will be found adequate. Often, satisfactory results can be achieved with much less, for example up to 100 ppm, even only up to or 10 ppm. based on the weight of peroxide in the composition.

The present invention is especially applicable to commercially-available grades of methyl ethyl ketone peroxide. These are compositions containing about 50% of organic peroxide in a suitable inert diluent, e.g. dimethyl phthalate. The methyl ethyl ketone peroxide content of such compositions is made up of several different peroxide constituents, according to the process by which it is manufactured. UK. patent specification No. 827,511 describes and claims one such process, and indicates the type of compounds which may be present. The term methyl ethyl ketone peroxide is used herein to include both the simple compound itself and the commercially-available compounds.

Thus, in accordance with a feature of this invention there is provided a composition consisting essentially of methyl ethyl ketone peroxide and an inert diluent, suitably dimethyl phthalate, and containing a stabilising quantity of dipicolinic acid. Preferably the peroxidic content of the composition is 50 to 60% and in such a case advantageously the quantity of dipicolinic acid employed is from 2 to 200 parts per million, preferably about 5 parts per million, based on the weight of the composition.

It has been found that dipicolinic acid is very difficult to dissolve directly in some liquids, for example in methyl ethyl ketone peroxide compositions, and normally some other means has to be found for introducing it.

According to a further feature, the invention provides a process for the production of a composition herein described, which comprises incorporating in the peroxidic mixture a solution of the dipicolinic acid in a solvent which is inert toward the peroxide and the acid.

Solvents other than acetic acid can be employed and may be preferred when used in connection with others of the organic peroxides mentioned herein. The main requirement is that the solvent'should be suitably inert toward the peroxide and dipicolinic acid.

The invention is further illustrated by the following examples.

In Example 1 stability is judged in terms of (a) percentage of available oxygen remaining after various periods of time, and (b) the acidity developed over the same periods. It is added that this development of acidity often accompanies decomposition of organic peroxides and is normally directly proportional to the loss of available oxygen due to decomposition. In Example 2 stability is measured in terms of available oxygen evolution.

The grades of methyl ethyl ketone peroxide referred to are those commercially available products containing 50% to 60% of peroxidic material in an inert diluent.

EXAMPLE 1 Methyl ethyl ketone peroxide stability on storage in polythene containers Acidity==Recorded as ml-s. N acid/ litre sample (a) 1.=Results on untreated M.E.K.P. (methyl ethyl ketone peroxide) 2.-=-Results on M.E.K.P. to 200 ml. of which has been added 0.1 ml. of a 4:1 solution of acetic acid in water 3.=-Results on M.E.K.P. stabilised with dipicolinic acid-- 5 ppm. (0.1 ml. of 1% solution of D.P.A. in 4:1 acetic acidzwater added to 200 ml. of M.E.K.P.)

3 tests were carried out on each sample.

triethyl phosphate. The tests were conducted as for Example 4 and the results are tabulated This example illustrates a comparative test with other known (organic) stabilisers for hydrogen peroxide. The test was conducted on the M.E.K.P. (R.G.S.) grade (referred to in Example 1) at 40 C. over a period of seven days. All the stabilisers were incorporated as solutions in acetic acid, to give a total of 5 p.p.m. Stability was measured in terms of gassing rate in vols./vol./year. The results are tabulated.

Dipicolinic Benzoic Quinaldic Control acid acid acid Mean over 7 days 3. 10 6. 12 6. 58 6. 43

The results show that benzoic acid is virtually ineffective, that quinaldic acid decreases rather than increases the stability and that dipicolinic acid gives very superior results.

I claim:

1. A composition comprising at least one ketone peroxide which is selected from the group consisting of methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide, or a hydroperoxide which is selected from the group consisting of tertiary butyl hydroperoxide and cumene hydroperoxide, with a stabilizing quantity of dipicolinic acid.

2. A composition according to claim 1 additionally comprising as an inert diluent, dimethyl phthalate or triethyl phosphate.

3. A composition according to claim 1 wherein the dipicolinic acid is present in amounts up to 500 parts per million.

4. A composition according to claim 1 wherein said dipicolinic acid is in a solution of acetic acid and water in the ratio of 4:1 respectively.

'5. A composition comprising cumene hydroperoxide and a stabilizing quantity of dipicolinic acid.

6. A composition comprising cyclohexanone peroxide, methyl cyclohexanone peroxide or mixtures thereof and a stabilizing quantity of dipicolinic acid.

7. A composition comprising t-butyl hydroperoxide and a stabilising quantity of dipicolinic acid.

8. A composition comprising at least one organic peroxide selected from the group consisting of methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide and cyclohexanone peroxide with a stabilizing quantity of dipicolinic acid.

References Cited UNITED STATES PATENTS 2,609,391 9/ 1952. Greenspan et al 260502 2,624,655 1/ 1953 Greenspan 23-2075 FOREIGN PATENTS 827,511 2/ 1960 Great Britain.

LEON ZITVER, Primary Examiner.

W. B. LONE, Assistant Examiner. 

